Science - June 13, 2013

Biomarkers show overexertion in horses

Lelystad researchers: overtraining of horses reflected in gene expression.

Sport horses that have been through overly strenuous training will show signs in the gen expression. These biomarkers may enable a method to be developed in the future that can easily detect signs of overtraining, says researcher Marinus Te Pas of Livestock Research. He considers overtraining of sport horses to be a serious problem that affects about 60 per cent of these horses. 'Even experienced trainers are often not fully aware of this.' Together with researchers in Utrecht, Te Pas looked for a way to detect overexertion in the muscles of an animal. To that end, he compared the RNA (the gene expression) in the muscle tissues of untrained, normally trained, over-trained and fully trained horses. He was struck by three aspects. In over-trained horses, the muscles are bound together in a way that is different from that of muscles in normally trained horses. Second, there is a higher gene expression of genes involved in cell death. Third, there is a decrease in the expression of genes that regulate the immune system. The gene expressions for these three characteristics are so different that they are suitable for use as biomarkers, he reported last month in The Veterinary Journal.
Te Pas has yet to find a practical measuring tool for this outcome. It would be a strain on horses if muscle tissues were to be taken from them on a routine basis. He is therefore seeking funding for a follow-up project to relate the RNA-expression to proteins in blood, saliva or urine.

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